The test harness polls CI about every 100ms, not every 10ms #204

Parent

#174

What to build

Make the harness start fewer processes while a Run waits on CI. The Run's poll interval can already be overridden by an environment variable for tests, and the harness sets it to 10ms, so every CI-wait scenario starts the fake gh about 100 times a second. Raise the harness value to about 100ms. If needed, adjust the CI grace period the harness sets so every CI-wait scenario still sees the states it tests: checks appearing, still running, passing, failing, absent. No product change.

Acceptance criteria

• The harness polls about every 100ms (the exact value is chosen from measurement)
• Every CI-related scenario still passes and still tests the same states
• The PR reports warm full-suite wall time and user + sys against the Make the test suite faster #174 baseline, plus the times of the CI-heavy binaries (ci, merge_run, spec_run) before and after
• The full suite passes

Blocked by

• Record the test suite baseline and make debug builds cheaper #202